1. Field of the Invention
The present invention generally relates to systems for monitoring the operation of fans through the use of electrical circuits, and in particular, to means for detecting the failure of cooling fans in a computer system and generating a plurality of signals in the event of such failure to provide warning messages and to control certain functions of the computer.
2. Description of the Prior Art
Computers generate heat when they are on and the generated heat needs to be dissipated. Heat dissipation in a computer system has a direct relationship to the stability and integrity of the operation of the computer system as well as its life expectancy. When a computer is not properly cooled, the computer may overheat and crash, the integrity of the system board may be compromised, and data may be lost. However, until recently, only the main frame and the mini computer manufacturers devoted any substantial amount of effort to the problem of heat dissipation. As a general proposition, an effective cooling system is expensive because it usually involves either placing the computer in an air-conditioned facility, or placing an expensive cooling system in or around the computer system and regularly servicing the cooling system.
On the other hand, personal computers or work stations such as the IBM or IBM compatible computers, MacIntosh computers, and Sun work stations typically operate at room temperature. In addition, these computers have to be price competitive and cannot afford to include expensive cooling systems. Thus, the extent of their cooling system is comprised of a fan that is part of the power supply, and maybe another fan directly attached to the CPU.
However, as the CPU speed of personal computers exceeds 50 MHz, cooling has become more and more important to the system life of the computer. In the current computer market the CPUs of most of the IBM compatible computers are running at anywhere from 33 MHz to 120 MHz. All of these high speed computer systems require that cooling fans be attached to the CPUs. However, given the fact that the cooling fan has become a critical component of the computer, there is no circuitry that monitors its operation. If the fan fails, the system will not be properly cooled, the temperature can quickly raise, and the system will crash and/or be damaged by the heat. Since the cooling fan is the critical component for providing heat dissipation in the computer system, a smart cooling security system is needed to monitor the cooling fan, and, in the event of a fan failure, to notify the user in an intelligent manner that the cooling fan has failed so that the user can save the files, turn off the power, and replace or repair the fan. To provide for the case where there are no users around, the cooling security system should also operate certain functions of the computer system in order to reduce heat generation.
Currently, there is only one product on the market that deals with the problem of overheating in the personal computer and/or workstation area. This device is a temperature sensor that can be attached to the chassis of the computer. When the temperature reaches a certain degree, the device generates a beeping noise. A computer user hearing the beeping sounds may or may not associate the beeping noise with an overheating condition since the computer generates beeping noises for a variety of reasons. If a user is not around, the computer may eventually overheat and crash. This product simply does not provide an effective method for notifying the user and for preventing an overheating condition. Thus, there is a desire for a low cost cooling security system that can detect potential overheating situations, provide warning messages, and trigger certain system functions to prevent the computer from actual overheating.